Method and apparatus for separating refuse from coal



Sept. 10, 1935. J. H. FLETCHER 2,014,249

METHOD AND APPARATUS FOR SEPAHATING REFUSE FROM COAL Original Filed Nov.21, 1930 2 Sheets- Sheet 1 Sept. 10, 1935- J. H. FLETCHER 2,014,249

METHOD AND APPARATUS FOR SEPARAT iNG REFUSE FROM GOAL I Original FiledNov. 21, 1930 2 Sheets-Sheet 2 Invenfi; limes fi/Eier Patented Sept. 10,1935 UNITED sr 'res METHOD AND APPARATUS FOR SEPARAT- ING REFUSE FROMCOAL 'James H. Fletcher, Wilmette,-lll., assignor, by mesne assignments,to Peale-Davis Company, Wilmington, Del., a corporation of DelawareApplication 2 Claims.

which combines the use of mechanical means and air under pressure foreffecting the separation.

Briefly described, an apparatus is used comprising an upper deck onwhich the material tov be separated is deposited, and a.lower deck forreceiving the refuse, the space between the decks being confined so thata superatmospheric air pressure may be maintained between the decks.Means is provided for reciprocating or moving the table so that thematerial on the upper deck will be agitated and urged along the tablefrom the receiving to the discharge end thereof. The upper deck isperforated or provided with a plurality of openings of a determinedsize, and the air pressure between the decks is maintained justsufliciently high so that the air jets flowing upwardly through theopenings or perforations will be just sufficient to support coalparticles of a size capable of passing through these openings, but

insuflicient to support the heavier refuse particles 3 of similar size.Suitable means is provided for Y discharging the refuse from thelower'deck without excessive loss of air pressure from the space betweenthe decks.

' The principal object of this invention is to provide an improvedmethod and apparatus for separating refuse from coal or similarmaterial,

such as briefly described hereinabove and dis,- closed more in detail inthe specifications which follow.

Another object is to provide an improved apparatus for air-cleaning coalor similar material.

Another object is to provide an improvedapparatus comprising a series ofsimilar separati g tables, each adapted to separate out refuse particlesof a substantially predetermined size.

Another object is to provide an improved air separatioirtable adapted tosuccessively but sepa- .rately withdraw refuse particles ofsubstantially predetermined sizes from the mass of mixed moi terials.Other objects and advantages of this invention will be more apparentfrom the following detailed description of certain approved form ofapparatus adapted to carry out the improved process herein disclosed.

In the accompanying drawings: Fig. 1 is a longitudinal vertical'sect'ionthrough a .simple form of the apparatus.

Fig. 2 is a plan view, partially broken away, of the apparatus shown inFig. 1.v v

November 21, 1930, Serial No. 497,142 Renewed January 24, 1935 p Fig. 3is a horizontal section of the apparatus taken substantially on the line3-3 of Fig. 1.

Fig. 4 is an enlarged vertical section through a fragment ofthe'separating table illustrating the separating process.

Fig. 5 is a diagrammatic side elevation illustrating a series or batteryof separators of the type shown in Fig. 1.

Fig. 6 is a partial verticalsection through a separating table embodyinga plurality of sepa- 10 rating zones, each adapted to divide out adifierent size of refuse particles.

Referring first to the simplified example of the apparatus asillustrated in Figs. 1, 2 and 3, the separating table indicated as anentirety at A is 15 suspended by a plurality af links I which arepivoted at their lower ends 2 to the table, and which are pivotallysupported at their upper ends 3 j from brackets 4 carried by an overheadsupporting structure 5. A pitman 6 pivoted to one end 20 of table A atI, has a collar 8 at its other end surrounding an eccentric 9 keyed onshaft III, which is rotated in any suitable manner. It will beapparentthat as the shaft I0 is rotated the eccentric will cause pitman 6 toreciprocate the table A and simultaneously give a small up and downmovement to the table, due to the oscillation of the supporting links I.

The table A comprises an upper deck II and alower deck l2 which arespaced apart to provide 30 an intervening chamber. l3 which is .closedon three sides by the vertical walls It, and which is closed at thedischarge end by a movable gate II.

A fan or other suitable air pumping mechanism l8 discharges air underpressure through conduit 35 ll provided with pressure-regulating valvell' into a chamber l8 having flexible side walls- IS, the upper side ofchamber" being closed by 'the lower deck I? of the table A. This lowerdeck is formed with a multiplicity of small perforations 20 whereby theair under pressure will be discharged from chamber it through lower deckI! into. the chamber l3 between the upper and lower decks of theseparating table. The upper deck II is formed with a plurality of holesor perforations 2|, thesi'ze or diameter of which is determined by thesize of. the refuse particles or lumps that are to be dischargedtherethrough' by gravity. The air pressure built up in chamber I! by fanIt will be regulated in accordance with the size of the openings II inthe upper'deck so that the force of the air jets passing upwardlythrough openings 2| will be justsufllcient to support particles of lumpsof coal capable of passing through 65.

indicated at :c.

the openings, but of insufiicient force to support the heavier refuseparticles of similar size.

The broken m'ass consisting of mixed coal and refuse is discharged ontoupper deck I I from a chute 22 and is confined on this deck by theupright walls 23 surrounding three sides of the table. A chute 24 at thedelivery end of the table serves to discharge the cleaned coal from thetable onto a conveyor 25 or any other suitable receiving means. A chute26 projects from the lower deck'IZ of the table for discharging refusefrom the lower deck onto a conveyor 21 or into any other suitablereceiving means. This chute 26 is I provided with a discharge gate 28 inaddition to the gate I5, already mentioned. The purpose of the two gatesI5 and 28 is to permit the discharge of solid material'from the lowerdeck I2' without an excessive loss of air pressure in the space betweenthe decks. The gate 28 will be closed and' the gate I5 opened until asufllcient quantity of refuse has collected in the chute 26, then thegate I5 will be closed and the gate 28 opened to discharge this refuseonto the conveyor ZI. Any other suitable forms of gates or valves couldbe used for this purpose, the mechanism hereinabove described beingmerely a diagrammatic example of apparatus suitable for this purpose.

Referring now more particularly to Fig. 4, the principle of operation ofthis improved apparatus and separating process will be more definitelydescribed. The separating table will be reciprocated so that the mass ofmixed material supported onthe upper deck II will be continuallyagitated and urged 'alongthe table in one direction, for example, inthe-direction of the arrow Air under pressure is forced through theopenings 20 in the lower deck I2 in sufiicient quantities to build up asuper-atmospheric pressure in the chamber I3 between the two decks sothat air jets will be directed upwardly through the several openings 2|in the upper table II, all as indicated by the small arrows in thedrawings. In thisflgure the lumps or particles of-refuse are heavilyshaded, whereas the particles of coal are indicated by lighter shading.The force of these air jets will be just sufficient to support lumps orparticles of coal, such as indicated at b, which-are small enough topass through one of the openings 2|. However, this air pressure is notsufllcient to support par- I ticles of refuse of similar size, asindicated at a,

and these pieces of refuse will drop through the openings 2I against theforce of the air streams and be caught by the lower deck I2. It isdesirable that the openings 20 in the lower deck may be made as small aspracticable so as to prevent the passage of refuse materialtherethrough,

but these openings should be in sumcient numbers to permit-a free flowof air upwardly through the lower deck so as to keep up the air pressurewithin the chamber I3. It will be apparent that larger lumps of coal,such as indicated at 0, would not be supported by the air pressure, butthese pieces are too large to pass through the openings 2I and will bemechanically supported uponthe upper deck II. Also smaller sizes ofcoal, such as indicated at d, will either be supported by the airpressure over the openings 2I or will be supported mechanically upon theupper deck I I, according to their-position on the table. As a result,all of the coal will .be maintained upon or above the upper deck II,whereas refuse of a predetermined size will be permitted to pass throughthe openings in the upper deck under the influence of gravity and'willbe upon the above the upper deck, butit is contemplated that thesesmaller sizes will be subsequently removed 5 by means of additionalseparating tables in which smaller openings are provided in the upperdeck and the air pressure is decreased.

One example of an apparatus embodying a series or battery of theseseparating tables is illustrated diagrammatically in Fig. 5. Each of theunits A, B and C may be of the type hereinabove described. The coal fromthe first separating table A, from which the larger particles of refusehave been removed, and discharged onto the conveyor 29, is dischargedfrom theupper deck onto the upper deck of the second separating table B.In this second table, the openings 2! in the upper deck are reduced insize and a decreased air pressure is used, whereby refuse particles of asmaller 20 size are permitted'to gravitate out of the mass and aredischarged from this second table onto the conveyor 30. The coal fromthe second table B is discharged onto the third table C'where a smallersize of refuse is separated out, and so on throughout the series.

Another form of the invention is indicated in Fig. 6 of the drawings. Inthis form a single long separating table is'used, the space between theupper and lower decks being separated by a plurality of transversevertical partitions 3| into a series of separate zones, such asindicated at 32, 33. 24 and 35, respectively. The openings in the upperdeck II are made successively smaller in the several zones throughoutthe series. For 85 example, in the zones as shown in Fig. 6, theopening's 3B .in the first zone 32 will be larger than the openings 31in the second zone 33, and the openings 38 in the third zone 34 will besmaller than the openings 31 in the second zone. The 40 I air pressuresmaintained in each of the separate zones will be correspondinglydecreased, whereby refuse particles of successively decreasing size willbe withdrawn from the mass as it is urged along the table in thedirection of the arrow, indicated at x- The refuse deposited on thelower deck I2 in each zone will be removed through traps or valves 39,as hereinabove described, and the cleaned coal will be discharged fromthe delivery end of the table at the end of the series 5 of zones.

While the expedient of providing the lower deck I2 with a multiplicityof small openings is desirable for maintaining a substantially uniformair pressure throughout the horizontal area of the table, or separatingzone, the air could be forced into the chamber I! through one or moreconduits communicating with either the bottom or sides of the chamber soas to maintain the desired air pressure between the upper and lowerdecks. In such case, an imperforate, or a substantially imperforatedlower deck I2 could be emciency of this improved method of separationdepends upon a certain definite ratio being maintained between threefactors, first, the number 7 and size of the openings in the upper deck,second,

the open area of the lower deck (which should have a multiplicity ofvery small holes), and third, the static'airpressure maintained betweenhe decks.

with these three factors properly balanced for the size of the refusethat is to be removed, any small size of the refuse, or other similarmaterial. can be separated out by this process. It will be noted thatthis process could be used for selecting out particles of a desired sizeof any relatively heavier material, from a mixed mass containing thismaterial.

It is to be understood that the simplified forms of apparatushereindisclosed are shown and described merely by way of example and that manyother designs of apparatus could be adapted for performing this improvedseparation process, all of which are intended to come within the termsof the claims which follow.

I claim:

1. A process of purifying coal which comprises maintaining a bed of rawcoal having a substantial variance in size of the pieces and particles,progressing said bed across a plurality oi pervious zones havingsuccessivelysmaller apertures therein, passing air currents upwardlythrough the traveling bed and regulating said air currents so as tosubject the zones with smaller apertures to lesser intensity of airaction and by said air regulation causing larger particles of refuse tofall through the coarsest apertures while floating the lighter materialand the flner'v refuse particles by air pressure and thereafter causingsaid finer refuse particles to fall through the smaller aperturesagainst the lesser air force while maintaining the lighter materialabove said apertures.

2. A process of purifying coal which comprises maintaining a bed ofsubstantially continuous raw coal having a substantial variance in sizeof the pieces and particles, progressing said bed across a plurality ofpervious zones having successively smaller apertures therein, passingair currents upwardly through substantially all parts of the travelingbed and regulating said air currents so as to subject the zones withsmaller apertures to lesser intensity of air action and by said airregulation causing larger particles of refuse to fall through thecoarsest apertures while floating the lighter material and the finerrefuse particles 29 by air pressure and thereafter causing said linerrefuse particles to fall through the smaller apertures against thelesser air force while main taining the lighter material above saidapertures.

JAMES H. FLETCHER.

